O-Ring Material Comparison Guide
Technical comparison of common elastomer materials including FKM (Viton®) to help select the optimal O-ring for your application.
Material Properties Comparison
| Property | NBR | HNBR | FKM (Viton®) | Fluorosilicone | Silicone | EPDM |
|---|---|---|---|---|---|---|
| Temperature Range | -30°C to +100°C | -40°C to +150°C | -20°C to +200°C ★ | -55°C to +200°C | -60°C to +230°C | -50°C to +150°C |
| Oil/Fuel Resistance | Good | Very Good | Excellent ★ | Very Good | Poor | Poor |
| Chemical Resistance | Good (oils) | Very Good | Excellent ★ | Excellent (fuels) | Fair | Good (polar) |
| Weather/Ozone Resistance | Poor | Good | Excellent | Excellent | Excellent | Outstanding ★ |
| Water/Steam Resistance | Fair | Good | Fair | Good | Good | Excellent ★ |
| Mechanical Strength | Excellent ★ | Very Good | Good | Fair | Poor | Good |
| Low-Temp Flexibility | Fair | Good | Fair | Excellent ★ | Excellent | Good |
| Compression Set | Fair | Good ★ | Good | Fair | Poor | Good |
| Cost | $ ★ | $$$ | $$$$ | $$$$$ | $$$$ | $$ |
★ = Best in class | Ratings are relative comparisons within this material group
Chemical Resistance Comparison
| Chemical/Fluid | NBR | HNBR | FKM | Fluorosilicone | Silicone | EPDM |
|---|---|---|---|---|---|---|
| Mineral Oil | Excellent ★ | Excellent | Excellent | Good | Poor ✗ | Poor ✗ |
| Gasoline | Good | Very Good | Excellent ★ | Very Good | Poor ✗ | Poor ✗ |
| Biodiesel | Fair | Good | Excellent ★ | Good | Poor ✗ | Poor ✗ |
| Jet Fuels | Fair | Very Good | Excellent ★ | Excellent | Poor ✗ | Poor ✗ |
| Hot Water | Fair | Good | Fair | Good | Good | Excellent ★ |
| Steam | Poor ✗ | Fair | Fair | Good | Good | Very Good ★ |
| Acids (dilute) | Fair | Good | Excellent ★ | Good | Fair | Good |
| Polar Solvents | Poor ✗ | Fair | Fair | Fair | Good | Excellent ★ |
Recommended Applications
FKM (Viton®) - Best For
- Aggressive chemical environments
- High-temperature fuel systems
- Automotive underhood components
- Oil/gas drilling equipment
- Seals for strong acids/bases
HNBR - Best For
- Cost-effective high-temp oil seals
- Biofuel applications
- Refrigeration systems
- Where better mechanical properties than FKM needed
Fluorosilicone - Best For
- Aerospace fuel systems
- Extreme low-temperature applications
- Military specifications
- Where flexibility and fuel resistance both needed
NBR - Best For
- Cost-sensitive oil applications
- General industrial seals
- Hydraulic systems
- Non-critical fuel systems
Silicone - Best For
- Food/medical applications
- High-temperature (non-oil) environments
- Electrical insulation
- Where flexibility is critical
EPDM - Best For
- Outdoor weathering applications
- Hot water/steam systems
- Brake systems (glycol-based)
- Polar solvent environments
Cost vs Performance Analysis
Relative performance across key properties
Material Selection Guidelines:
- For maximum chemical resistance: FKM
- Best cost-performance balance: HNBR
- Extreme low temperatures: Fluorosilicone
- Budget oil resistance: NBR
- Outdoor/weathering: EPDM